The early golf ball, known as a featherie, consisted of a leather pouch filled with goose feathers. In order to obtain a hard ball, the pouch was usually filled while wet with wet goose feathers. Since it was widely believed that a smooth sphere would result in less drag, and thus fly farther, the pouch was stitched inside out. Once the pouch was filled with feathers, it was stitched shut. In this manner, a golf ball could be constructed with few stitches on the outside of the ball. In many instances, the ball was then dried, oiled, and painted white. The typical drive with this type of ball was about 150 to 175 yards. However, once this ball became wet, it could no longer be used.
Around 1845, the gutta-percha ball was introduced. This ball was made from the gum of the Malaysian Sapodilla tree. Typically, the gum was heated and molded into a sphere, resulting in a very smooth surface. The typical drive with the gutta-percha ball was shorter than that obtained with the featherie. Around this time, many golfers began to notice that older balls that were beat up with nicks, bumps, and other surface irregularities seemed to fly farther. As golf balls evolved, golfers began to seek beat up golf balls because they provided an advantage over smooth balls.
As golf ball research progressed, manufacturers began to realize that including dimples on the surface of the golf ball would allow it to fly farther. The nicks and bumps of previous golf balls, and the dimples of modern golf balls, provide an aerodynamic advantage over a smooth surface. Engineers discovered that the dimples act as “turbulators” in the layer of air next to the ball (the “boundary layer”). In some situations, a turbulent boundary layer is capable of reducing drag, which in turn increases the distance that a golf ball is capable of flying.
The flow of air around an object may be described as laminar and turbulent. Laminar flow has less drag, but it is also susceptible to a phenomenon called “separation.” Once separation of a laminar boundary layer occurs, the drag rises dramatically because of eddies that form in the wake. Turbulent flow has more drag initially but also better adhesion, and therefore is less prone to separation. Therefore, engineers learned that if the shape of an object is such that separation occurs easily, it is better to perturb the boundary layer, at the slight cost of increased skin friction drag, in order to increase adhesion and reduce eddies. Typically, this means a significant reduction in drag. Thus, dimples are included on the surface of golf balls in order to perturb the boundary layer. Dimples on a golf ball are a symmetrical way of creating the same turbulence in the boundary layer that nicks and cuts did on previous golf balls.
Golf ball manufacturers are constantly searching for more efficient methods of changing the surface of a golf ball in order to reduce drag and thereby increase the distance that a golf ball is capable of flying.